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ti_iic.c revision 1.13
      1 /* $NetBSD: ti_iic.c,v 1.13 2021/01/27 03:10:20 thorpej Exp $ */
      2 
      3 /*
      4  * Copyright (c) 2013 Manuel Bouyer.  All rights reserved.
      5  *
      6  * Redistribution and use in source and binary forms, with or without
      7  * modification, are permitted provided that the following conditions
      8  * are met:
      9  * 1. Redistributions of source code must retain the above copyright
     10  *    notice, this list of conditions and the following disclaimer.
     11  * 2. Redistributions in binary form must reproduce the above copyright
     12  *    notice, this list of conditions and the following disclaimer in the
     13  *    documentation and/or other materials provided with the distribution.
     14  *
     15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     25  */
     26 
     27 /*-
     28  * Copyright (c) 2012 Jared D. McNeill <jmcneill (at) invisible.ca>
     29  * All rights reserved.
     30  *
     31  * Redistribution and use in source and binary forms, with or without
     32  * modification, are permitted provided that the following conditions
     33  * are met:
     34  * 1. Redistributions of source code must retain the above copyright
     35  *    notice, this list of conditions and the following disclaimer.
     36  * 2. The name of the author may not be used to endorse or promote products
     37  *    derived from this software without specific prior written permission.
     38  *
     39  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     40  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     41  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     42  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     43  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     44  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     45  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     46  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     47  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     48  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     49  * SUCH DAMAGE.
     50  */
     51 
     52 #include <sys/cdefs.h>
     53 __KERNEL_RCSID(0, "$NetBSD: ti_iic.c,v 1.13 2021/01/27 03:10:20 thorpej Exp $");
     54 
     55 #include <sys/param.h>
     56 #include <sys/systm.h>
     57 #include <sys/device.h>
     58 #include <sys/conf.h>
     59 #include <sys/bus.h>
     60 #include <sys/proc.h>
     61 #include <sys/kernel.h>
     62 #include <sys/mutex.h>
     63 #include <sys/condvar.h>
     64 
     65 #include <dev/i2c/i2cvar.h>
     66 
     67 #include <dev/fdt/fdtvar.h>
     68 
     69 #include <arm/ti/ti_prcm.h>
     70 #include <arm/ti/ti_iicreg.h>
     71 
     72 #ifndef OMAP2_I2C_SLAVE_ADDR
     73 #define OMAP2_I2C_SLAVE_ADDR	0x01
     74 #endif
     75 
     76 #define OMAP2_I2C_FIFOBYTES(fd)	(8 << (fd))
     77 
     78 #ifdef I2CDEBUG
     79 #define DPRINTF(args)	printf args
     80 #else
     81 #define DPRINTF(args)
     82 #endif
     83 
     84 enum ti_iic_type {
     85 	TI_IIC_OMAP3,
     86 	TI_IIC_OMAP4,
     87 	TI_NTYPES
     88 };
     89 
     90 enum {
     91 	I2C_SYSC,
     92 	I2C_IRQSTATUS_RAW,
     93 	I2C_IRQSTATUS,
     94 	I2C_IRQENABLE,		/* OMAP3 */
     95 	I2C_IRQENABLE_SET,	/* OMAP4 */
     96 	I2C_IRQENABLE_CLR,	/* OMAP4 */
     97 	I2C_SYSS,
     98 	I2C_BUF,
     99 	I2C_CNT,
    100 	I2C_DATA,
    101 	I2C_CON,
    102 	I2C_OA,
    103 	I2C_SA,
    104 	I2C_PSC,
    105 	I2C_SCLL,
    106 	I2C_SCLH,
    107 	I2C_BUFSTAT,
    108 	TI_NREGS
    109 };
    110 
    111 static const u_int ti_iic_regmap[TI_NTYPES][TI_NREGS] = {
    112 	[TI_IIC_OMAP3] = {
    113 		[I2C_SYSC] = 0x20,
    114 		[I2C_IRQSTATUS_RAW] = 0x08,
    115 		[I2C_IRQSTATUS] = 0x08,
    116 		[I2C_IRQENABLE] = 0x04,
    117 		[I2C_SYSS] = 0x10,
    118 		[I2C_BUF] = 0x14,
    119 		[I2C_CNT] = 0x18,
    120 		[I2C_DATA] = 0x1c,
    121 		[I2C_CON] = 0x24,
    122 		[I2C_OA] = 0x28,
    123 		[I2C_SA] = 0x2c,
    124 		[I2C_PSC] = 0x30,
    125 		[I2C_SCLL] = 0x34,
    126 		[I2C_SCLH] = 0x38,
    127 		[I2C_BUFSTAT] = 0x40,
    128 	},
    129 	[TI_IIC_OMAP4] = {
    130 		[I2C_SYSC] = 0x10,
    131 		[I2C_IRQSTATUS_RAW] = 0x24,
    132 		[I2C_IRQSTATUS] = 0x28,
    133 		[I2C_IRQENABLE_SET] = 0x2c,
    134 		[I2C_IRQENABLE_CLR] = 0x30,
    135 		[I2C_SYSS] = 0x90,
    136 		[I2C_BUF] = 0x94,
    137 		[I2C_CNT] = 0x98,
    138 		[I2C_DATA] = 0x9c,
    139 		[I2C_CON] = 0xa4,
    140 		[I2C_OA] = 0xa8,
    141 		[I2C_SA] = 0xac,
    142 		[I2C_PSC] = 0xb0,
    143 		[I2C_SCLL] = 0xb4,
    144 		[I2C_SCLH] = 0xb8,
    145 		[I2C_BUFSTAT] = 0xc0,
    146 	},
    147 };
    148 
    149 static const struct device_compatible_entry compat_data[] = {
    150 	/* compatible			type */
    151 	{ .compat = "ti,omap3-i2c",	.value = TI_IIC_OMAP3 },
    152 	{ .compat = "ti,omap4-i2c",	.value = TI_IIC_OMAP4 },
    153 	DEVICE_COMPAT_EOL
    154 };
    155 
    156 /* operation in progress */
    157 typedef enum {
    158 	TI_I2CREAD,
    159 	TI_I2CWRITE,
    160 	TI_I2CDONE,
    161 	TI_I2CERROR
    162 } ti_i2cop_t;
    163 
    164 struct ti_iic_softc {
    165 	device_t		sc_dev;
    166 	struct i2c_controller	sc_ic;
    167 	kmutex_t		sc_lock;
    168 	device_t		sc_i2cdev;
    169 
    170 	bus_space_tag_t		sc_iot;
    171 	bus_space_handle_t	sc_ioh;
    172 
    173 	enum ti_iic_type	sc_type;
    174 
    175 	void			*sc_ih;
    176 	kmutex_t		sc_mtx;
    177 	kcondvar_t		sc_cv;
    178 	ti_i2cop_t		sc_op;
    179 	int			sc_opflags;
    180 	int			sc_buflen;
    181 	int			sc_bufidx;
    182 	char			*sc_buf;
    183 
    184 	bool			sc_busy;
    185 
    186 	int			sc_rxthres;
    187 	int			sc_txthres;
    188 };
    189 
    190 #define I2C_READ_REG(sc, reg)		\
    191 	bus_space_read_2((sc)->sc_iot, (sc)->sc_ioh, ti_iic_regmap[(sc)->sc_type][(reg)])
    192 #define I2C_READ_DATA(sc)		\
    193 	bus_space_read_1((sc)->sc_iot, (sc)->sc_ioh, ti_iic_regmap[(sc)->sc_type][I2C_DATA])
    194 #define I2C_WRITE_REG(sc, reg, val)	\
    195 	bus_space_write_2((sc)->sc_iot, (sc)->sc_ioh, ti_iic_regmap[(sc)->sc_type][(reg)], (val))
    196 #define I2C_WRITE_DATA(sc, val)		\
    197 	bus_space_write_1((sc)->sc_iot, (sc)->sc_ioh, ti_iic_regmap[(sc)->sc_type][I2C_DATA], (val))
    198 
    199 static int	ti_iic_match(device_t, cfdata_t, void *);
    200 static void	ti_iic_attach(device_t, device_t, void *);
    201 
    202 static int	ti_iic_intr(void *);
    203 
    204 static int	ti_iic_acquire_bus(void *, int);
    205 static void	ti_iic_release_bus(void *, int);
    206 static int	ti_iic_exec(void *, i2c_op_t, i2c_addr_t, const void *,
    207 			       size_t, void *, size_t, int);
    208 
    209 static int	ti_iic_reset(struct ti_iic_softc *);
    210 static int	ti_iic_op(struct ti_iic_softc *, i2c_addr_t, ti_i2cop_t,
    211 			       uint8_t *, size_t, int);
    212 static void	ti_iic_handle_intr(struct ti_iic_softc *, uint32_t);
    213 static void	ti_iic_do_read(struct ti_iic_softc *, uint32_t);
    214 static void	ti_iic_do_write(struct ti_iic_softc *, uint32_t);
    215 
    216 static int	ti_iic_wait(struct ti_iic_softc *, uint16_t, uint16_t, int);
    217 static uint32_t	ti_iic_stat(struct ti_iic_softc *, uint32_t);
    218 static int	ti_iic_flush(struct ti_iic_softc *);
    219 
    220 CFATTACH_DECL_NEW(ti_iic, sizeof(struct ti_iic_softc),
    221     ti_iic_match, ti_iic_attach, NULL, NULL);
    222 
    223 static int
    224 ti_iic_match(device_t parent, cfdata_t match, void *opaque)
    225 {
    226 	struct fdt_attach_args * const faa = opaque;
    227 
    228 	return of_compatible_match(faa->faa_phandle, compat_data);
    229 }
    230 
    231 static void
    232 ti_iic_attach(device_t parent, device_t self, void *opaque)
    233 {
    234 	struct ti_iic_softc *sc = device_private(self);
    235 	struct fdt_attach_args * const faa = opaque;
    236 	const int phandle = faa->faa_phandle;
    237 	int fifodepth, fifo;
    238 	const char *modname;
    239 	char intrstr[128];
    240 	bus_addr_t addr;
    241 	bus_size_t size;
    242 
    243 	if (fdtbus_get_reg(phandle, 0, &addr, &size) != 0) {
    244 		aprint_error(": couldn't get registers\n");
    245 		return;
    246 	}
    247 	if (!fdtbus_intr_str(phandle, 0, intrstr, sizeof(intrstr))) {
    248 		aprint_error(": couldn't decode interrupt\n");
    249 		return;
    250 	}
    251 
    252 	if (ti_prcm_enable_hwmod(phandle, 0) != 0) {
    253 		aprint_error(": couldn't enable module\n");
    254 		return;
    255 	}
    256 
    257 	sc->sc_dev = self;
    258 	sc->sc_iot = faa->faa_bst;
    259 	mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_NONE);
    260 	mutex_init(&sc->sc_mtx, MUTEX_DEFAULT, IPL_NET);
    261 	cv_init(&sc->sc_cv, "tiiic");
    262 	iic_tag_init(&sc->sc_ic);
    263 	sc->sc_ic.ic_cookie = sc;
    264 	sc->sc_ic.ic_acquire_bus = ti_iic_acquire_bus;
    265 	sc->sc_ic.ic_release_bus = ti_iic_release_bus;
    266 	sc->sc_ic.ic_exec = ti_iic_exec;
    267 
    268 	if (bus_space_map(sc->sc_iot, addr, size, 0, &sc->sc_ioh) != 0) {
    269 		aprint_error(": couldn't map registers\n");
    270 		return;
    271 	}
    272 	sc->sc_type = of_compatible_lookup(phandle, compat_data)->value;
    273 
    274 	sc->sc_ih = fdtbus_intr_establish_xname(phandle, 0, IPL_NET, 0,
    275 	    ti_iic_intr, sc, device_xname(self));
    276 	if (sc->sc_ih == NULL) {
    277 		aprint_error(": couldn't establish interrupt\n");
    278 		return;
    279 	}
    280 
    281 	modname = fdtbus_get_string(phandle, "ti,hwmods");
    282 	if (modname == NULL)
    283 		modname = fdtbus_get_string(OF_parent(phandle), "ti,hwmods");
    284 
    285 	fifodepth = I2C_BUFSTAT_FIFODEPTH(I2C_READ_REG(sc, I2C_BUFSTAT));
    286 	fifo = OMAP2_I2C_FIFOBYTES(fifodepth);
    287 	sc->sc_rxthres = sc->sc_txthres = fifo >> 1;
    288 
    289 	aprint_naive("\n");
    290 	if (modname != NULL)
    291 		aprint_normal(": I2C controller (%s), %d-bytes FIFO\n", modname, fifo);
    292 	else
    293 		aprint_normal(": I2C controller (i2c@%" PRIxBUSADDR "), %d-bytes FIFO\n",
    294 		    addr, fifo);
    295 
    296 	ti_iic_reset(sc);
    297 	ti_iic_flush(sc);
    298 
    299 	fdtbus_register_i2c_controller(&sc->sc_ic, phandle);
    300 
    301 	fdtbus_attach_i2cbus(self, phandle, &sc->sc_ic, iicbus_print);
    302 }
    303 
    304 static int
    305 ti_iic_intr(void *arg)
    306 {
    307 	struct ti_iic_softc *sc = arg;
    308 	uint32_t stat;
    309 
    310 	mutex_enter(&sc->sc_mtx);
    311 	DPRINTF(("ti_iic_intr opflags=%#x\n", sc->sc_opflags));
    312 	if ((sc->sc_opflags & I2C_F_POLL) == 0) {
    313 		stat = I2C_READ_REG(sc, I2C_IRQSTATUS);
    314 		DPRINTF(("ti_iic_intr pre handle sc->sc_op eq %#x\n", sc->sc_op));
    315 		ti_iic_handle_intr(sc, stat);
    316 		I2C_WRITE_REG(sc, I2C_IRQSTATUS, stat);
    317 		if (sc->sc_op == TI_I2CERROR || sc->sc_op == TI_I2CDONE) {
    318 			DPRINTF(("ti_iic_intr post handle sc->sc_op %#x\n", sc->sc_op));
    319 			cv_broadcast(&sc->sc_cv);
    320 		}
    321 	}
    322 	mutex_exit(&sc->sc_mtx);
    323 	DPRINTF(("ti_iic_intr status 0x%x\n", stat));
    324 	return 1;
    325 }
    326 
    327 static int
    328 ti_iic_acquire_bus(void *opaque, int flags)
    329 {
    330 	struct ti_iic_softc *sc = opaque;
    331 
    332 	mutex_enter(&sc->sc_lock);
    333 	while (sc->sc_busy)
    334 		cv_wait(&sc->sc_cv, &sc->sc_lock);
    335 	sc->sc_busy = true;
    336 	mutex_exit(&sc->sc_lock);
    337 
    338 	return 0;
    339 }
    340 
    341 static void
    342 ti_iic_release_bus(void *opaque, int flags)
    343 {
    344 	struct ti_iic_softc *sc = opaque;
    345 
    346 	mutex_enter(&sc->sc_lock);
    347 	sc->sc_busy = false;
    348 	cv_broadcast(&sc->sc_cv);
    349 	mutex_exit(&sc->sc_lock);
    350 }
    351 
    352 static int
    353 ti_iic_exec(void *opaque, i2c_op_t op, i2c_addr_t addr,
    354     const void *cmdbuf, size_t cmdlen, void *buf, size_t len, int flags)
    355 {
    356 	struct ti_iic_softc *sc = opaque;
    357 	int err;
    358 
    359 	DPRINTF(("ti_iic_exec: op 0x%x cmdlen %zd len %zd flags 0x%x\n",
    360 	    op, cmdlen, len, flags));
    361 
    362 	if (cmdlen > 0) {
    363 		err = ti_iic_op(sc, addr, TI_I2CWRITE,
    364 		    __UNCONST(cmdbuf), cmdlen,
    365 		    (I2C_OP_READ_P(op) ? 0 : I2C_F_STOP) | flags);
    366 		if (err)
    367 			goto done;
    368 	}
    369 
    370 	if (I2C_OP_STOP_P(op))
    371 		flags |= I2C_F_STOP;
    372 
    373 	/*
    374 	 * I2C controller doesn't allow for zero-byte transfers.
    375 	 */
    376 	if (len == 0) {
    377 		err = EINVAL;
    378 		goto done;
    379 	}
    380 
    381 	if (I2C_OP_READ_P(op)) {
    382 		err = ti_iic_op(sc, addr, TI_I2CREAD, buf, len, flags);
    383 	} else {
    384 		err = ti_iic_op(sc, addr, TI_I2CWRITE, buf, len, flags);
    385 	}
    386 
    387 done:
    388 	if (err)
    389 		ti_iic_reset(sc);
    390 
    391 	ti_iic_flush(sc);
    392 
    393 	DPRINTF(("ti_iic_exec: done %d\n", err));
    394 	return err;
    395 }
    396 
    397 static int
    398 ti_iic_reset(struct ti_iic_softc *sc)
    399 {
    400 	uint32_t psc, scll, sclh;
    401 	int i;
    402 
    403 	DPRINTF(("ti_iic_reset\n"));
    404 
    405 	/* Disable */
    406 	I2C_WRITE_REG(sc, I2C_CON, 0);
    407 	/* Soft reset */
    408 	I2C_WRITE_REG(sc, I2C_SYSC, I2C_SYSC_SRST);
    409 	delay(1000);
    410 	/* enable so that we can check for reset complete */
    411 	I2C_WRITE_REG(sc, I2C_CON, I2C_CON_EN);
    412 	delay(1000);
    413 	for (i = 0; i < 1000; i++) { /* 1s delay for reset */
    414 		if (I2C_READ_REG(sc, I2C_SYSS) & I2C_SYSS_RDONE)
    415 			break;
    416 	}
    417 	/* Disable again */
    418 	I2C_WRITE_REG(sc, I2C_CON, 0);
    419 	delay(50000);
    420 
    421 	if (i >= 1000) {
    422 		aprint_error_dev(sc->sc_dev, ": couldn't reset module\n");
    423 		return 1;
    424 	}
    425 
    426 
    427 	/* XXX standard speed only */
    428 	if (sc->sc_type == TI_IIC_OMAP3) {
    429 		psc = (96000000 / 19200000) - 1;
    430 		scll = sclh = (19200000 / (2 * 100000)) - 6;
    431 	} else {
    432 		psc = 3;
    433 		scll = 53;
    434 		sclh = 55;
    435 	}
    436 
    437 	/* Clocks */
    438 	I2C_WRITE_REG(sc, I2C_PSC, psc);
    439 	I2C_WRITE_REG(sc, I2C_SCLL, scll);
    440 	I2C_WRITE_REG(sc, I2C_SCLH, sclh);
    441 
    442 	/* Own I2C address */
    443 	I2C_WRITE_REG(sc, I2C_OA, OMAP2_I2C_SLAVE_ADDR);
    444 
    445 	/* 5 bytes fifo */
    446 	I2C_WRITE_REG(sc, I2C_BUF,
    447 	    I2C_BUF_RXTRSH(sc->sc_rxthres) | I2C_BUF_TXTRSH(sc->sc_txthres));
    448 
    449 	/* Enable */
    450 	I2C_WRITE_REG(sc, I2C_CON, I2C_CON_EN);
    451 
    452 	return 0;
    453 }
    454 
    455 static int
    456 ti_iic_op(struct ti_iic_softc *sc, i2c_addr_t addr, ti_i2cop_t op,
    457     uint8_t *buf, size_t buflen, int flags)
    458 {
    459 	uint16_t con, stat, mask;
    460 	int err, retry;
    461 
    462 	KASSERT(op == TI_I2CREAD || op == TI_I2CWRITE);
    463 	DPRINTF(("ti_iic_op: addr %#x op %#x buf %p buflen %#x flags %#x\n",
    464 	    addr, op, buf, (unsigned int) buflen, flags));
    465 
    466 	mask = I2C_IRQSTATUS_ARDY | I2C_IRQSTATUS_NACK | I2C_IRQSTATUS_AL;
    467 	if (op == TI_I2CREAD) {
    468 		mask |= I2C_IRQSTATUS_RDR | I2C_IRQSTATUS_RRDY;
    469 	} else {
    470 		mask |= I2C_IRQSTATUS_XDR | I2C_IRQSTATUS_XRDY;
    471 	}
    472 
    473 	err = ti_iic_wait(sc, I2C_IRQSTATUS_BB, 0, flags);
    474 	if (err) {
    475 		DPRINTF(("ti_iic_op: wait error %d\n", err));
    476 		return err;
    477 	}
    478 
    479 	con = I2C_CON_EN;
    480 	con |= I2C_CON_MST;
    481 	con |= I2C_CON_STT;
    482 	if (flags & I2C_F_STOP)
    483 		con |= I2C_CON_STP;
    484 	if (addr & ~0x7f)
    485 		con |= I2C_CON_XSA;
    486 	if (op == TI_I2CWRITE)
    487 		con |= I2C_CON_TRX;
    488 
    489 	mutex_enter(&sc->sc_mtx);
    490 	sc->sc_op = op;
    491 	sc->sc_opflags = flags;
    492 	sc->sc_buf = buf;
    493 	sc->sc_buflen = buflen;
    494 	sc->sc_bufidx = 0;
    495 
    496 	I2C_WRITE_REG(sc, I2C_CON, I2C_CON_EN | I2C_CON_MST | I2C_CON_STP);
    497 	DPRINTF(("ti_iic_op: op %d con 0x%x ", op, con));
    498 	I2C_WRITE_REG(sc, I2C_CNT, buflen);
    499 	I2C_WRITE_REG(sc, I2C_SA, (addr & I2C_SA_MASK));
    500 	DPRINTF(("SA 0x%x len %d\n", I2C_READ_REG(sc, I2C_SA), I2C_READ_REG(sc, I2C_CNT)));
    501 
    502 	if ((flags & I2C_F_POLL) == 0 || sc->sc_type == TI_IIC_OMAP3) {
    503 		/* clear any pending interrupt */
    504 		I2C_WRITE_REG(sc, I2C_IRQSTATUS,
    505 		    I2C_READ_REG(sc, I2C_IRQSTATUS));
    506 		/* and enable */
    507 		if (sc->sc_type == TI_IIC_OMAP4) {
    508 			I2C_WRITE_REG(sc, I2C_IRQENABLE_SET, mask);
    509 		} else {
    510 			I2C_WRITE_REG(sc, I2C_IRQENABLE, mask);
    511 		}
    512 	}
    513 	/* start transfer */
    514 	I2C_WRITE_REG(sc, I2C_CON, con);
    515 
    516 	if ((flags & I2C_F_POLL) == 0) {
    517 		/* and wait for completion */
    518 		DPRINTF(("ti_iic_op waiting, op %#x\n", sc->sc_op));
    519 		while (sc->sc_op == op) {
    520 			if (cv_timedwait(&sc->sc_cv, &sc->sc_mtx,
    521 			    mstohz(5000)) == EWOULDBLOCK) {
    522 				/* timeout */
    523 				op = TI_I2CERROR;
    524 			}
    525 		}
    526 		DPRINTF(("ti_iic_op waiting done, op %#x\n", sc->sc_op));
    527 
    528 		/* disable interrupts */
    529 		if (sc->sc_type == TI_IIC_OMAP4) {
    530 			I2C_WRITE_REG(sc, I2C_IRQENABLE_CLR, 0xffff);
    531 		} else {
    532 			I2C_WRITE_REG(sc, I2C_IRQENABLE, 0);
    533 		}
    534 	} else {
    535 		/* poll for completion */
    536 		DPRINTF(("ti_iic_op polling, op %x\n", sc->sc_op));
    537 		while (sc->sc_op == op) {
    538 			stat = ti_iic_stat(sc, mask);
    539 			DPRINTF(("ti_iic_op stat 0x%x\n", stat));
    540 			if (stat == 0) {
    541 				/* timeout */
    542 				sc->sc_op = TI_I2CERROR;
    543 			} else {
    544 				ti_iic_handle_intr(sc, stat);
    545 			}
    546 			I2C_WRITE_REG(sc, I2C_IRQSTATUS, stat);
    547 		}
    548 		DPRINTF(("ti_iic_op polling done, op now %x\n", sc->sc_op));
    549 	}
    550 	mutex_exit(&sc->sc_mtx);
    551 	retry = 10000;
    552 	I2C_WRITE_REG(sc, I2C_CON, 0);
    553 	while (I2C_READ_REG(sc, I2C_CON) & I2C_CON_MST) {
    554 		delay(100);
    555 		if (--retry == 0)
    556 			break;
    557 	}
    558 	return (sc->sc_op == TI_I2CDONE) ? 0 : EIO;
    559 }
    560 
    561 static void
    562 ti_iic_handle_intr(struct ti_iic_softc *sc, uint32_t stat)
    563 {
    564 	KASSERT(mutex_owned(&sc->sc_mtx));
    565 	KASSERT(stat != 0);
    566 	DPRINTF(("ti_iic_handle_intr stat %#x\n", stat));
    567 
    568 	if (stat &
    569 	    (I2C_IRQSTATUS_NACK|I2C_IRQSTATUS_AL)) {
    570 		sc->sc_op = TI_I2CERROR;
    571 		return;
    572 	}
    573 	if (stat & I2C_IRQSTATUS_ARDY) {
    574 		sc->sc_op = TI_I2CDONE;
    575 		return;
    576 	}
    577 	if (sc->sc_op == TI_I2CREAD)
    578 		ti_iic_do_read(sc, stat);
    579 	else if (sc->sc_op == TI_I2CWRITE)
    580 		ti_iic_do_write(sc, stat);
    581 	else
    582 		return;
    583 }
    584 void
    585 ti_iic_do_read(struct ti_iic_softc *sc, uint32_t stat)
    586 {
    587 	int len = 0;
    588 
    589 	KASSERT(mutex_owned(&sc->sc_mtx));
    590 	DPRINTF(("ti_iic_do_read stat %#x\n", stat));
    591 	if (stat & I2C_IRQSTATUS_RDR) {
    592 		len = I2C_READ_REG(sc, I2C_BUFSTAT);
    593 		len = I2C_BUFSTAT_RXSTAT(len);
    594 		DPRINTF(("ti_iic_do_read receive drain len %d left %d\n",
    595 		    len, I2C_READ_REG(sc, I2C_CNT)));
    596 	} else if (stat & I2C_IRQSTATUS_RRDY) {
    597 		len = sc->sc_rxthres + 1;
    598 		DPRINTF(("ti_iic_do_read receive len %d left %d\n",
    599 		    len, I2C_READ_REG(sc, I2C_CNT)));
    600 	}
    601 	for (;
    602 	    sc->sc_bufidx < sc->sc_buflen && len > 0;
    603 	    sc->sc_bufidx++, len--) {
    604 		sc->sc_buf[sc->sc_bufidx] = I2C_READ_DATA(sc);
    605 		DPRINTF(("ti_iic_do_read got b[%d]=0x%x\n", sc->sc_bufidx,
    606 		    sc->sc_buf[sc->sc_bufidx]));
    607 	}
    608 	DPRINTF(("ti_iic_do_read done\n"));
    609 }
    610 
    611 void
    612 ti_iic_do_write(struct ti_iic_softc *sc, uint32_t stat)
    613 {
    614 	int len = 0;
    615 
    616 	DPRINTF(("ti_iic_do_write stat %#x\n", stat));
    617 	KASSERT(mutex_owned(&sc->sc_mtx));
    618 	if (stat & I2C_IRQSTATUS_XDR) {
    619 		len = I2C_READ_REG(sc, I2C_BUFSTAT);
    620 		len = I2C_BUFSTAT_TXSTAT(len);
    621 		DPRINTF(("ti_iic_do_write xmit drain len %d left %d\n",
    622 		    len, I2C_READ_REG(sc, I2C_CNT)));
    623 	} else if (stat & I2C_IRQSTATUS_XRDY) {
    624 		len = sc->sc_txthres + 1;
    625 		DPRINTF(("ti_iic_do_write xmit len %d left %d\n",
    626 		    len, I2C_READ_REG(sc, I2C_CNT)));
    627 	}
    628 	for (;
    629 	    sc->sc_bufidx < sc->sc_buflen && len > 0;
    630 	    sc->sc_bufidx++, len--) {
    631 		DPRINTF(("ti_iic_do_write send b[%d]=0x%x\n",
    632 		    sc->sc_bufidx, sc->sc_buf[sc->sc_bufidx]));
    633 		I2C_WRITE_DATA(sc, sc->sc_buf[sc->sc_bufidx]);
    634 	}
    635 	DPRINTF(("ti_iic_do_write done\n"));
    636 }
    637 
    638 static int
    639 ti_iic_wait(struct ti_iic_softc *sc, uint16_t mask, uint16_t val, int flags)
    640 {
    641 	int retry = 10;
    642 	uint16_t v;
    643 	DPRINTF(("ti_iic_wait mask %#x val %#x flags %#x\n", mask, val, flags));
    644 
    645 	while (((v = I2C_READ_REG(sc, I2C_IRQSTATUS_RAW)) & mask) != val) {
    646 		--retry;
    647 		if (retry == 0) {
    648 			aprint_error_dev(sc->sc_dev, ": wait timeout, "
    649 			    "mask = %#x val = %#x stat = %#x\n",
    650 			    mask, val, v);
    651 			return EBUSY;
    652 		}
    653 		if (flags & I2C_F_POLL) {
    654 			delay(50000);
    655 		} else {
    656 			kpause("tiiic", false, mstohz(50), NULL);
    657 		}
    658 	}
    659 	DPRINTF(("ti_iic_wait done retry %#x\n", retry));
    660 
    661 	return 0;
    662 }
    663 
    664 static uint32_t
    665 ti_iic_stat(struct ti_iic_softc *sc, uint32_t mask)
    666 {
    667 	uint32_t v;
    668 	int retry = 500;
    669 	DPRINTF(("ti_iic_wait mask %#x\n", mask));
    670 	while (--retry > 0) {
    671 		v = I2C_READ_REG(sc, I2C_IRQSTATUS_RAW) & mask;
    672 		if (v != 0)
    673 			break;
    674 		delay(100);
    675 	}
    676 	DPRINTF(("ti_iic_wait done retry %#x\n", retry));
    677 	return v;
    678 }
    679 
    680 static int
    681 ti_iic_flush(struct ti_iic_softc *sc)
    682 {
    683 	DPRINTF(("ti_iic_flush\n"));
    684 #if 0
    685 	int retry = 1000;
    686 	uint16_t v;
    687 
    688 	while ((v = I2C_READ_REG(sc, I2C_IRQSTATUS_RAW)) & I2C_IRQSTATUS_RRDY) {
    689 		if (--retry == 0) {
    690 			aprint_error_dev(sc->sc_dev,
    691 			    ": flush timeout, stat = %#x\n", v);
    692 			return EBUSY;
    693 		}
    694 		(void)I2C_READ_DATA(sc);
    695 		delay(1000);
    696 	}
    697 #endif
    698 
    699 	I2C_WRITE_REG(sc, I2C_CNT, 0);
    700 	return 0;
    701 }
    702